2018 saw Total open up a gap as the Mena region’s largest liquids producer, while BP’s gas output soared. The first months of 2019 were characterized by Eni laying the groundwork for future gains but plenty of opportunities remain for IOCs to snap up acreage.

The world’s largest oil firms have been increasingly drawn towards the US unconventional scene in recent years, and the trend is accelerating. ExxonMobil and Chevron announced eye-catching plans earlier this year to...